全文获取类型
收费全文 | 2701篇 |
免费 | 167篇 |
国内免费 | 3篇 |
出版年
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 23篇 |
2018年 | 21篇 |
2017年 | 26篇 |
2016年 | 42篇 |
2015年 | 54篇 |
2014年 | 72篇 |
2013年 | 220篇 |
2012年 | 126篇 |
2011年 | 122篇 |
2010年 | 84篇 |
2009年 | 95篇 |
2008年 | 154篇 |
2007年 | 142篇 |
2006年 | 147篇 |
2005年 | 138篇 |
2004年 | 158篇 |
2003年 | 144篇 |
2002年 | 161篇 |
2001年 | 40篇 |
2000年 | 35篇 |
1999年 | 44篇 |
1998年 | 47篇 |
1997年 | 41篇 |
1996年 | 29篇 |
1995年 | 49篇 |
1994年 | 36篇 |
1993年 | 46篇 |
1992年 | 48篇 |
1991年 | 50篇 |
1990年 | 40篇 |
1989年 | 39篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 37篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1977年 | 20篇 |
1976年 | 27篇 |
1975年 | 13篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1972年 | 16篇 |
排序方式: 共有2871条查询结果,搜索用时 31 毫秒
1.
Akio Tsuji 《Luminescence》1991,6(1):1-1
It was with great sadness that we received news of the sudden death on 29 August 1990 of Professor Toshio Goto who was a member of the Editorial Board of this Journal. 相似文献
2.
Akio Matsuura Takako Nagayama Takayasu Kitagawa 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,617(2)
An automated high-performance liquid chromatographic method for the determination of the diuretic drug furosemide has been established. Dog plasma was injected directly into a two-column system with a BSA—ODS (ODS column coated with bovine serum albumin) precolumn and a C18 analytical column for the separation of furosemide. The two columns were automatically switched. Furosemide remained trapped on the precolumn while proteins were eluted to waste. After column switching, furosemide was washed onto the analytical column and analysed without interference. The greatest advantage of the method is its easy performance without manual sample preparation; it requires no extraction or deproteinization. The method allows determination of 0.1–10 μg/ml of furosemide with accuracy and precision comparable with previously reported values. The coefficients of variation obtained from replicate measurements of 1 μg/ml and 5 μg/ml samples were 1.65% and 2.40%, respectively. This method was used to measure the plasma levels of furosemide in beagle dogs to whom the drugs was administered, as a reference, in a toxicological study. 相似文献
3.
4.
We investigated whether the adoptive transfer of H-2-incompatible lymphokine-activated killer (LAK) cells would efficiently demonstrate antitumor activity without damaging the normal host cells. Allogeneic LAK cells (5 X 10(7] did not cause graft-versus-host disease (GVHD) in irradiated recipients, whereas more than half of the mice transferred with the same dose of fresh allogeneic spleen cells developed GVHD. Repeated transfer (three times at 4-day intervals, 1.2 X 10(8) cells/mouse) did not result in GVHD. Graft-versus-host reaction (GVHR), which is detectable by spleen enlargement of recipients transferred with allogeneic lymphoid cells was also absent in LAK cell-transferred mice of all strain combinations tested. Host immune responses were not affected in these mice. Therefore, it is feasible to transfer allogeneic LAK cells. With the antitumor efficacy of allogeneic LAK cells, they preferentially lysed allogeneic tumor targets. Adoptive transfer of the allogeneic LAK cells led to a significant decrease in the lung-colonizing foci of intravenously inoculated B16 melanoma cells. Allogeneic LAK cells and syngeneic ones were equally active, in vivo. The use of allogeneic LAK cells may prove to be a valuable method for effective clinical antitumor immunotherapy. 相似文献
5.
Participation of IE antigens (Ag) in immune response as the transplantation Ag was examined. IE- B10.A(4R)(4R; Kk, IAk, IE-, Db) mice could not reject skin graft from IE Ag alone-disparate B10.A(2R) (2R; Kk, IAk, IEk, Db) mice despite intravenous (iv) injection of 2R spleen cells (SC) before or after skin grafting, indicating that graft rejection could not be caused across IE Ag-barrier alone. Furthermore, 4R SC could not induce lethal graft-versus-host disease (GVHD) in supralethally (950 rad) irradiated 2R mice. On the other hand, infiltration of lymphoid cells was observed at the site of transplanted 2R skin in 4R mice. SC of 4R mice unprimed or primed with 2R skin or 2R SC showed the capability to proliferate in vitro in response to 2R Ag. In immunofluorescence analysis of lymph node cells (LNC) of 4R mice injected iv with 2R SC 7 days earlier, IE-reactive CD4+Vbeta 11+ T cells did not change in number, but slightly increased the expression of interleukin-2 receptor (IL-2R). In 2R mice irradiated with 670 rad and injected iv with 4R SC 7 days earlier, 4R-derived CD4+V beta 11+ T cells proliferated, changed to blastoid form, and showed a markedly increased expression of IL-2R. To further investigate the influence of IE alloantigens on transplantation immunity, IL-2 production and anti-class I CTL activity were assayed. The 4R SC capable of recognizing IEk and Dk Ag of B10.BR (Kk, IAk, IEk, Dk) generated levels of both IL-2 and CTL activities higher than those of 2R SC capable of recognizing Dk Ag alone. These results strongly suggest that IE alloantigens indirectly act as the transplantation Ag by the stimulation of IE-reactive CD4+ helper T cells resulting in the differentiation of class I-restricted CD8+ T cells. 相似文献
6.
7.
We investigated the effects of near-infrared irradiation on the photoconversion of Chenopodium album water-soluble chlorophyll-binding protein (CaWSCP) in the presence of sodium hydrosulfite and found a further photoconversion from CP742 to CP763, a novel form of CaWSCP. Interestingly, one-third of the absorption peak at 668 nm was recovered in CP763, but re-irradiation under oxidative conditions eliminated the photo convertibility of CaWSCP. 相似文献
8.
Takemi Yoshida Akio Uchida Toshinori Yamamoto Yukio Kuroiwa 《Biochimica et Biophysica Acta (BBA)/General Subjects》1981,677(2):280-286
The activities of mitochondrial type A and B monoamine oxidase were determined in the liver of rats fed a diet containing 2-acetylaminofluorene (AAF). Three days after the initiation of AAF-feeding, there was a significant decrease of type B monoamine oxidase activity without affect on type A enzyme. The decreased activity of type B monoamine oxidase, which reached a minimum after three weeks, was sustained for as long as AAF-feeding was continued. Sex-related difference in response to AAF was seen in the rat with respect to the onset and the intensity of the decreased type B monoamine oxidase activity, male rats being more sensitive to the carcinogen than female rats. In contrast to the in vivo effect, AAF showed a potent inhibitory effect on type A monoamine oxidase, rather than on type B enzyme, when added in vitro. The pI50 values were estimated to be 7.5 against type A monoamine oxidase and 4.1 against type B enzyme, respectively. The in vitro inhibition of both types of monoamine oxidase by AAF was competitive. The Ki values for AAF were calculated to be 9.51 · 10?9 M for type A monoamine oxidase and 1.30 · 10?5 M for type B enzyme, respectively. In accordance with the potent inhibitory effect of AAF on type A monoamine oxidase in vitro, a single administration of the carcinogen, at a dose of 50 mg/kg, resulted in a marked and temporal decrease of the enzyme activity in the mitochondria of male rat liver. Recovery of the decreased type B monoamine oxidase activity was slow, and the enzyme activity did not return to control levels, even if rats were fed the basal diet for 2 or 4 weeks after the cessation of AAF-feeding. 相似文献
9.
Shigeo Koyasu Makoto Asada Akio Fukuda Yoshimi Okada 《Journal of molecular biology》1981,153(2):471-475
The mode of polymerization of two species of flagellins, flagellin A and flagellin B, in polar flagella of Caulobacter crescentus was examined. By immunological staining we found that 1 to 1.2 μm of the portion of the flagellar filament proximal to the cell was composed of flagellin B, whereas about 5 μm of the distal portion was composed of flagellin A. This result, together with the previous observation that a flagellin B-less mutant cannot form normal flagella but instead forms stubs in spite of their high level of flagellin A synthesis, indicates that flagellin B is very important for the formation of complete flagella and/or for the initiation of filament formation from the hook. 相似文献
10.
Effect of Glycine on Thiazole Biosynthesis in Escherichia coli 总被引:1,自引:0,他引:1
Glycine was found to replace thiamine thiazole for the growth of the thiazoleless mutant of Escherichia coli; it also stimulated the production of thiamine thiazole by washed cell suspensions of the mutant. 相似文献